Fix the tracking of min recovery point timeline.

hlinnaka · hlinnaka · commit 6be799664aa8 · 2012-12-10T16:04:26.000+02:00
Forgot to update it at the right place. Also, consider checkpoint record
that switches to new timelne to be on the new timeline.

This fixes erroneous "requested timeline 2 does not contain minimum recovery
point" errors, pointed out by Amit Kapila while testing another patch.
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
@@ -605,6 +605,7 @@ static void SetLatestXTime(TimestampTz xtime);
 static void SetCurrentChunkStartTime(TimestampTz xtime);
 static void CheckRequiredParameterValues(void);
 static void XLogReportParameters(void);
+static void checkTimeLineSwitch(XLogRecPtr lsn, TimeLineID newTLI);
 static void LocalSetXLogInsertAllowed(void);
 static void CheckPointGuts(XLogRecPtr checkPointRedo, int flags);
 static void KeepLogSeg(XLogRecPtr recptr, XLogSegNo *logSegNo);
@@ -5909,12 +5910,41 @@ StartupXLOG(void)
 					LWLockRelease(XidGenLock);
 				}
 
+				/*
+				 * Before replaying this record, check if it is a shutdown
+				 * checkpoint record that causes the current timeline to
+				 * change. The checkpoint record is already considered to be
+				 * part of the new timeline, so we update ThisTimeLineID
+				 * before replaying it. That's important so that replayEndTLI,
+				 * which is recorded as the minimum recovery point's TLI if
+				 * recovery stops after this record, is set correctly.
+				 */
+				if (record->xl_rmid == RM_XLOG_ID &&
+					(record->xl_info & ~XLR_INFO_MASK) == XLOG_CHECKPOINT_SHUTDOWN)
+				{
+					CheckPoint	checkPoint;
+					TimeLineID	newTLI;
+
+					memcpy(&checkPoint, XLogRecGetData(record), sizeof(CheckPoint));
+					newTLI = checkPoint.ThisTimeLineID;
+
+					if (newTLI != ThisTimeLineID)
+					{
+						/* Check that it's OK to switch to this TLI */
+						checkTimeLineSwitch(EndRecPtr, newTLI);
+
+						/* Following WAL records should be run with new TLI */
+						ThisTimeLineID = newTLI;
+					}
+				}
+
 				/*
 				 * Update shared replayEndRecPtr before replaying this record,
 				 * so that XLogFlush will update minRecoveryPoint correctly.
 				 */
 				SpinLockAcquire(&xlogctl->info_lck);
 				xlogctl->replayEndRecPtr = EndRecPtr;
+				xlogctl->replayEndTLI = ThisTimeLineID;
 				SpinLockRelease(&xlogctl->info_lck);
 
 				/*
@@ -7858,6 +7888,48 @@ UpdateFullPageWrites(void)
 	END_CRIT_SECTION();
 }
 
+/*
+ * Check that it's OK to switch to new timeline during recovery.
+ *
+ * 'lsn' is the address of the shutdown checkpoint record we're about to
+ * replay. (Currently, timeline can only change at a shutdown checkpoint).
+ */
+static void
+checkTimeLineSwitch(XLogRecPtr lsn, TimeLineID newTLI)
+{
+	/*
+	 * The new timeline better be in the list of timelines we expect
+	 * to see, according to the timeline history. It should also not
+	 * decrease.
+	 */
+	if (newTLI < ThisTimeLineID || !tliInHistory(newTLI, expectedTLEs))
+		ereport(PANIC,
+				(errmsg("unexpected timeline ID %u (after %u) in checkpoint record",
+						newTLI, ThisTimeLineID)));
+
+	/*
+	 * If we have not yet reached min recovery point, and we're about
+	 * to switch to a timeline greater than the timeline of the min
+	 * recovery point: trouble. After switching to the new timeline,
+	 * we could not possibly visit the min recovery point on the
+	 * correct timeline anymore. This can happen if there is a newer
+	 * timeline in the archive that branched before the timeline the
+	 * min recovery point is on, and you attempt to do PITR to the
+	 * new timeline.
+	 */
+	if (!XLogRecPtrIsInvalid(minRecoveryPoint) &&
+		XLByteLT(lsn, minRecoveryPoint) &&
+		newTLI > minRecoveryPointTLI)
+		ereport(PANIC,
+				(errmsg("unexpected timeline ID %u in checkpoint record, before reaching minimum recovery point %X/%X on timeline %u",
+						newTLI,
+						(uint32) (minRecoveryPoint >> 32),
+						(uint32) minRecoveryPoint,
+						minRecoveryPointTLI)));
+
+	/* Looks good */
+}
+
 /*
  * XLOG resource manager's routines
  *
@@ -7971,44 +8043,13 @@ xlog_redo(XLogRecPtr lsn, XLogRecord *record)
 		}
 
 		/*
-		 * TLI may change in a shutdown checkpoint.
+		 * We should've already switched to the new TLI before replaying this
+		 * record.
 		 */
 		if (checkPoint.ThisTimeLineID != ThisTimeLineID)
-		{
-			/*
-			 * The new timeline better be in the list of timelines we expect
-			 * to see, according to the timeline history. It should also not
-			 * decrease.
-			 */
-			if (checkPoint.ThisTimeLineID < ThisTimeLineID ||
-				!tliInHistory(checkPoint.ThisTimeLineID, expectedTLEs))
-				ereport(PANIC,
-						(errmsg("unexpected timeline ID %u (after %u) in checkpoint record",
-								checkPoint.ThisTimeLineID, ThisTimeLineID)));
-
-			/*
-			 * If we have not yet reached min recovery point, and we're about
-			 * to switch to a timeline greater than the timeline of the min
-			 * recovery point: trouble. After switching to the new timeline,
-			 * we could not possibly visit the min recovery point on the
-			 * correct timeline anymore. This can happen if there is a newer
-			 * timeline in the archive that branched before the timeline the
-			 * min recovery point is on, and you attempt to do PITR to the
-			 * new timeline.
-			 */
-			if (!XLogRecPtrIsInvalid(minRecoveryPoint) &&
-				XLByteLT(lsn, minRecoveryPoint) &&
-				checkPoint.ThisTimeLineID > minRecoveryPointTLI)
-				ereport(PANIC,
-						(errmsg("unexpected timeline ID %u in checkpoint record, before reaching minimum recovery point %X/%X on timeline %u",
-								checkPoint.ThisTimeLineID,
-								(uint32) (minRecoveryPoint >> 32),
-								(uint32) minRecoveryPoint,
-								minRecoveryPointTLI)));
-
-			/* Following WAL records should be run with new TLI */
-			ThisTimeLineID = checkPoint.ThisTimeLineID;
-		}
+			ereport(PANIC,
+					(errmsg("unexpected timeline ID %u (should be %u) in checkpoint record",
+							checkPoint.ThisTimeLineID, ThisTimeLineID)));
 
 		RecoveryRestartPoint(&checkPoint);
 	}
